JP2007154575A - Earthquake resistance structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reinforce an existing filled ground without demolishing the existing filled ground and prevent liquefaction phenomenon from being caused even when earthquake or the like occurs. <P>SOLUTION: A number of tubular members 4 having at least one opened end and a number of holes formed in a longitudinal direction are inserted in a longitudinal direction (in the direction of an arrow X) of the filled ground 2 from above the filled ground 2 with the opened end upward, and a number of the tubular members 4 are arranged in line in a columnar shape to form a group 7 of the tubular members. A plurality of groups 7 of the tubular members are closely arranged in a horizontal direction (in the direction of an arrow Y) of the filled ground 2 and a tubular member block 8 is formed by the plurality of the groups 7 of the tubular members. A plurality of the tubular member blocks 8 are arranged in a horizontal direction of the filled ground 2 with a predetermined separating distance T. The filled ground 2 is divided into a plurality of clod areas 9 by the tubular member blocks 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a seismic structure, and more particularly to a seismic structure for embankments.

  Since the embankment is usually made of sandy soil, when an earthquake occurs, a liquefaction phenomenon occurs near the boundary with the natural ground and loses stability, and the sandy soil moves along the boundary. Therefore, the embankment is more likely to collapse than the natural ground, and various seismic structures have been proposed.

  For example, Patent Document 1 proposes an embankment structure including a rigid body that extends substantially horizontally over substantially the entire lower part of the embankment structure, and a drain disposed below the rigid body.

  This Patent Document 1 is intended to take earthquake resistance measures at the time of embankment construction, and by arranging a rigid body at the lower part of the embankment structure, it is possible to uniformly disperse the stress generated inside the embankment structure. In addition, by arranging the drain, it is possible to prevent an increase in the pore pressure of groundwater and intrusion into the embankment structure of the groundwater, thereby causing liquefaction in the underground of the foundation ground. However, the settlement amount of the embankment structure is equalized.

  Further, in Patent Document 2, a steel sheet pile wall is formed around a limited area on a conventional ground, and the upper surface is the deepest point on the conventional ground on the inner side of the planned center position of the ground structure. A high strength intermediate layer is formed so that it becomes a mortar shape, and then the upper layer of ordinary earth and sand is layered repeatedly on the upper part of this intermediate layer, and the method of building a seismic ground is to fill Proposed.

  Similarly to Patent Document 1, this Patent Document 2 is also intended to take anti-seismic measures at the time of embankment construction, and an earthquake occurs by constructing the upper surface of the intermediate layer that is unlikely to soften the ground into a mortar-shaped inclined surface. Even if the liquefaction phenomenon occurs, the earth and sand are collected directly under the target structure, so that the decrease in ground strength and the settlement are attempted to be suppressed.

  Furthermore, in Patent Document 3, reinforcing plate-like bodies are embedded in two rows and columns in the longitudinal direction of the substantially central portion of the embankment that has been embanked, and the upper ends of the two reinforcing plate-like bodies are connected at predetermined intervals. The seismic performance reinforcement structure of the levee body which has a double cut-off structure connected by the above has been proposed.

  This Patent Document 3 is designed to make an existing embankment ground quake-proof by using a reinforcing material. By making a double-cut-off structure with a reinforcing plate and a connecting member, an earthquake occurs. Sometimes the horizontal displacement of the dam body just below the top of the bank can be suppressed, and the settlement of the bank top is suppressed, so that the water storage performance of the earth fill dam and the reservoir can be sufficiently secured.

JP-A-2005-290712 JP-A-6-65911 JP 2003-321826 A

  However, in Patent Document 1 and Patent Document 2, when a ground structure such as a house already exists on the existing embankment, the ground structure must be dismantled once and a portion to be reinforced must be dug back. The buried embankment can be constructed only in the longitudinal direction, the degree of construction freedom is limited, and there is also a problem in drainage, so that there is a problem that it is still insufficient as a liquefaction prevention measure.

  In Patent Document 3, since the reinforcing plates embedded in two columns in the longitudinal direction are at right angles to the direction in which the sliding force acts, the structure prevents slipping only by rigidity, and the seismic reinforcement is large. In addition to the fact that it has to be of a large scale, there is a problem that since the reinforcing plate is embedded, it is easy to cause an increase in pore water pressure in the event of an earthquake, and this is not a sufficient liquefaction prevention measure.

  The present invention has been made in view of such circumstances, reinforcing the embankment without destroying the existing embankment, and preventing the occurrence of liquefaction even if an earthquake or the like occurs. The purpose is to provide a seismic structure.

  In order to achieve the above object, the seismic structure according to the present invention has a large number of tubular members, at least one end of which is an open end and a large number of holes formed in the longitudinal direction, in the longitudinal direction of the embankment from the embankment. A tubular member group is formed in which a large number of tubular members are inserted and arranged in a columnar shape, and a plurality of tubular member groups are arranged close to each other in the transverse direction of the embankment, and the plurality of tubular members A tubular member block is formed in a group, and a plurality of the tubular member blocks are disposed with a predetermined separation distance in a transverse direction of the embankment, and the embankment is formed by a plurality of the tubular member blocks. It is characterized by being divided into soil blocks.

  Further, the earthquake-resistant structure of the present invention is characterized in that the predetermined separation distance is 10 times or less with respect to the depth of the embankment.

  Moreover, the seismic structure of the present invention is characterized in that a water collecting pipe having a number of holes formed in the longitudinal direction is embedded in the soil mass region in the longitudinal direction of the embankment.

  According to the above earthquake-resistant structure, a large number of tubular members having at least one open end and a large number of holes formed in the longitudinal direction are penetrated from the embankment in the longitudinal direction of the embankment, and the numerous tubular members Are formed in a columnar shape, and a plurality of the tubular member groups are arranged close to each other in the transverse direction of the embankment, and a tubular member block is formed by the plurality of tubular member groups. And the plurality of tubular member blocks are arranged with a predetermined separation distance in the transverse direction of the embankment, and the embankment is divided into a plurality of clot regions by the tubular member blocks. The tubular member block becomes a resistor against the embankment, and the collapse of the embankment can be effectively suppressed. That is, the resistance at the side of the tubular member block is relatively large with respect to the resistance of the bottom surface of the liquefied embankment, which makes the embankment difficult to slide, and even if an earthquake or the like occurs, Collapse can be prevented in advance.

  In addition, since the tubular member is formed with a large number of holes in the longitudinal direction, pore water due to excess pore water pressure during an earthquake flows into the tubular member through the holes, thereby reducing the excess pore water pressure. And the liquefaction phenomenon can be effectively prevented.

  Moreover, the desired effect mentioned above can be obtained by making the said predetermined separation distance into 10 times or less with respect to the depth of the embankment.

  Furthermore, since the water collecting pipe in which a number of holes are formed in the longitudinal direction is embedded in the clot region in the longitudinal direction of the embankment, the pore water is drained to the outside through the water collecting pipe. The excess pore water pressure can be reduced, and the liquefaction phenomenon can be effectively prevented.

  Next, an embodiment of the present invention will be described in detail.

  FIG. 1 is a schematic diagram showing an outline of an embodiment of an earthquake-resistant structure according to the present invention. A banking ground 2 is formed in a stepped manner on an inclined natural ground 1, and on each banking ground 2. There is a ground structure 3 such as a house. A tubular member 4 is embedded in the embankment 2.

  2A and 2B are views showing the appearance of the tubular member 4, in which FIG. 2A is a front view and FIG. 2B is a view taken along the line BB in FIG. 2A.

  As shown in FIG. 2, the tubular member 4 has one end as an open end 5, the other end is crushed into a flat shape and closed in a substantially sharp shape, and a number of holes 6 are provided in the longitudinal direction. Yes. In the present embodiment, the holes 6 are formed in a long hole shape and are arranged in a staggered pattern in the circumferential direction.

  3 is an enlarged view of a portion A in FIG. 1, FIG. 4 is a sectional view taken along the line CC in FIG. 3, and FIG. 5 is a sectional view taken along the line DD in FIG.

  That is, as shown in FIG. 3, the tubular member 4 extends from the soft embankment 2 to the hard natural ground 1 with the open end 5 facing upward, and the longitudinal direction of the embankment 2 from the embankment 2 (arrow X). The tubular member group 7 is formed by arranging a large number of tubular members 4 in a columnar shape.

  As shown in FIG. 4, the tubular member group 7 is arranged in two rows and columns with a predetermined proximity distance t (for example, 2 to 3 m), and the tubular member group 8 in the two rows of tubular member groups 7. Is formed.

  Further, a plurality of tubular member blocks 8 are arranged with a predetermined separation distance T in the transverse direction (indicated by an arrow Y) of the embankment land 1, and the embankment land 2 is divided into a plurality of by the tubular member block 8. Divided into a clot region 9.

  Here, as shown in FIG. 5, the separation distance T is set to be 10 times or less the depth (filling depth) D of the embankment board 2. The lower limit value of the separation distance T is not particularly limited, but is preferably up to about 1 m in consideration of cost and workability.

  In such an earthquake-resistant structure, since the tubular member block 8 has an effect as a resistor against the collapse of the embankment 2, the embankment can be prevented from collapsing. Moreover, even if the pore water pressure rises due to an earthquake or the like, the pore water is guided to the hole 5 of the tubular member 4 and drained to the outside, so that the excess pore water pressure is dissipated, thereby causing a liquefaction phenomenon. It can be prevented in advance.

  That is, according to the present embodiment, by dividing the embankment land 2 into a plurality of mass regions 9, the embankment 2 can be prevented from collapsing, and the tubular member penetrated into the embankment 2. Since a large number of holes 6 are formed in 4, it is possible to dissipate excess pore water pressure at the time of an earthquake and the like, and to prevent the liquefaction phenomenon from occurring.

  FIG. 6 is a diagram showing a construction state of the tubular member 4 on the embankment 2, and the tubular member 4 can be easily placed on the embankment 2 by a boring device or the like and can penetrate into the natural ground 1.

  In particular, the diameter of the tubular member 4 may be about 60 mm to 100, so that it can be placed in the embankment floor 2 with a simple construction machine such as a concrete breaker. Even if the object 3 is constructed, it can be constructed by vibrating, press-fitting and driving the tubular member 4 under the floor.

  As described above, according to the present embodiment, it is possible to easily and quickly perform the earthquake resistant construction on the existing embankment 2 without dismantling the ground structure 3, and the workability is excellent.

  FIG. 7 is a schematic diagram showing an outline of the second embodiment of the seismic structure according to the present invention. In the second embodiment, the water collecting pipe 10 is buried in the longitudinal direction of the embankment 2. Yes.

  Specifically, the water collecting pipe 10 is connected to a tubular member similar to that shown in FIG. 2 via a joint member (not shown), and is embedded in the earth region 9 as shown in FIG.

  According to the second embodiment, even if the pore water pressure increases due to the occurrence of an earthquake or the like, the pore water is collected in the water collecting pipe 10 and drained to the outside. In combination with the action of the tubular member block 8, further increase in the pore water pressure is suppressed, and the occurrence of the liquefaction phenomenon can be effectively prevented.

  The present invention is not limited to the above embodiment. In the above-described embodiment, the tubular member block 8 is configured by the tubular member group 7 in two rows and columns, but the tubular member block 8 may be configured by the tubular member group 7 having three or more columns.

It is the schematic diagram which showed the outline of one Embodiment (1st Embodiment) of the earthquake-resistant structure which concerns on this invention. It is the figure which showed the external appearance of the tubular member, Comprising: Fig.2 (a) is a front view, FIG.2 (b) is a BB arrow line view of Fig.2 (a). Implementation chart of the present invention It is the A section enlarged view of FIG. 5 is a cross-sectional view taken along the line DD of FIG. It is CC sectional drawing of FIG. It is DD sectional drawing of FIG. It is a figure which shows the construction state to the embankment of a tubular member. It is the schematic diagram which showed the outline of 2nd Embodiment of the earthquake-resistant structure which concerns on this invention. It is principal part sectional drawing of 2nd Embodiment.

Explanation of symbols

2 Embankment 4 Tubular member 5 Open end 6 Hole 7 Tubular member group 8 Tubular member block 9 Clot region

Claims (3)

A large number of tubular members having at least one end as an open end and a large number of holes formed in the longitudinal direction are penetrated from the embankment to the longitudinal direction of the embankment with the open end facing upward, and the numerous tubular members A tubular member group is formed in a columnar shape,
A plurality of the tubular member groups are arranged close to each other in the transverse direction of the embankment, and a tubular member block is formed by the plurality of tubular member groups,
A plurality of the tubular member blocks are disposed with a predetermined separation distance in a transverse direction of the embankment,
The seismic structure, wherein the embankment is divided into a plurality of soil blocks by the tubular member block.   The earthquake-resistant structure according to claim 1, wherein the predetermined separation distance is 10 times or less with respect to the depth of the embankment.   2. The earthquake-resistant structure according to claim 1, wherein a water collecting pipe having a plurality of holes formed in a longitudinal direction is embedded in the soil mass region in a longitudinal direction of the embankment.

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